This invention is a polychromatic pen cartridge for a recording device such as a color plotter or printer or the like for recording a color image on a recording medium, said color image characterized by a line width, comprising tapered lumen tubular means comprising plural hollow elongate lumen means, said tubular means having a tip end facing said recording medium and spanning a distance on said recording medium on the order of said line width, each lumen means having an opening at said tip end of said tubular means, each lumen means being characterized by a large input opening at the other end of said tubular means, a plurality of separate ink reservoirs connected to corresponding ones of said lumen means at the input openings thereof, and means for individually controlling ink flow from each of said ink reservoirs to a respective one of said lumen means.
Plotters or printers which record a graphic image on a media surface move an ink cartridge in contact with the media surface in X and Y directions over the surface of the media. Typically, the ink emitted by the cartridge is black or some other dark color, and the recorded image is a monotone image. In attempting to form a color image, two approaches may be used. One is to record in succession several monotone images of different colors on the same media surface using different cartridges containing different ink colors. Another approach would be to employ several separately activated different color pens held closely together and moved in unison relative to the media surface. The advantage of the latter approach is that it would be very fast, requiring only a single pass across the media to record a multi-colored image. The disadvantage of the latter approach is that the resolution of the recorded image would be very poor because the smallest size of a single multi-colored dot would be the combined tip areas of all of the pens. Thus, such an approach is unsatisfactory. The disadvantage of the first approach is that it is time consuming (due to the recording of a succession of images on the same media) and the alignment or registration of the plural images with each other can be problematical. Any misalignment between the successive images will create either color errors or loss of resolution or both. Where such problems are eliminated by the use of precision controls, the advantage of the first approach is that it provides a much higher resolution image than the second approach.
Yet another approach would be to inject different colored inks into the same cartridge at different positions on the media. This would provide the high resolution corresponding to the tip area of a single pen cartridge and the speed of recording all the colors of a multi-colored image in a single pass. The disadvantage of this approach, however, is that at a point of transition in the image between one distinct color and another, ink of the one color would still be flowing out of the pen tip just as ink of the other color begins to enter the input of the pen. All of the ink of the one color must be expelled through the tip before the recorded color can change. Thus, the color resolution would be very poor due to the residual amount of ink carried in the pen/tip assembly and due to the finite amount of time required to expel the residual ink when changing ink colors.
It has not seemed possible to realize the advantages of both high recording speed (i.e., single pass multi-colored image recording) and high resolution (i.e., minimum recorded image dot size equal to the tip area of a single pen cartridge) in a pen-cartridge plotter. The techniques for realizing each of these advantages do not seem to be mutually compatible.
Accordingly, it is an object of the present invention to provide a completely new approach which records multi-colored images with an ink or pen cartridge in a single pass with the resolution of a single pen cartridge.
It is another object of the present invention to provide a completely new approach which records multi-colored images with an ink or pen cartridge in a single pass with the resolution of a single pen cartridge without requiring that the ink of one color be flushed out of the pen before recording with the ink of another color.
Other objects and benefits of the invention will become apparent from the detailed description which follows hereinafter when taken in conjunction with the drawing figures which accompany it.